Vacuum-drying apparatus



May 31, 1966 cs. BETTANlN 3,253,351

VACUUM-*DRYING APPARATUS Filed Feb. 5, 1963 l CLOSURE MECHANISM r- [0 FOR APERTURES 12 1 i l l INVENTOR. GIUSEPPE BETTANIN 44 TTORNE Y United States Patent Oice 3,253,351 VACUUM-DRYING APPARATUS Giuseppe Bettanin, 19 Via A Ferrarin, Thiene, Vicenza, Italy Filed Feb. 5, 1963, Ser. No. 256,452 7 Claims. (Cl. 34-92) The present invention relates to a machine for drying hides and skins, and more particularly, relates to a machine, operating under vacuum, for drying tanned hydes or skins which effectively prevents recondensation of moisture.

It is known in the prior art to utilize heating means for rapid drying of skins or hides, and, in some instances, also heating means together with a vacuum.

However, the prior art processes involve generally a rather long drying period due to the fact that during the opening phase for 'repressurization, cold air is admitted which produces recondensation, thereby preventing the perfect, complete drying of the skin or hide.

The present invention relates to a machine which has been conceived and realized for the purpose of accelerating the drying periods and rendering the drying operation as perfect and complete as possible, and which constitutes a significant improvement over the most advanced known machines in the field.

These known prior art machines are generally provided with only a single heating plate, namely a lower heating plate on which is placed the skin or hide to be dried.

A member forming a concave surface is normally disposed in these prior art machines above the single heating plate thereof in which the vacuum is established in such a manner that the thus-constituted depression favors the evaporation during drying.

It is obvious that in order to establish in these prior art machines the atmospheric equilibrium to enable opening of the covermember, it is necessary to admit outside air which, being colder than the air inside of the cover, recondenses the water vapor still present in this cavity, thereby causing droplets to fall again on the dried portions of the skins or hides.

In the machine proposed according to the present invention, it is precisely this cover part which has been improved by providing above the aforementioned member forming the concave surface a second layer in the form of another heating plate, and above the latter a further chamber intended to collect the air which is heated by the last-mentioned heating plate of the second layer to be admitted after heating thereof into the vacuum chamber prior to opening of the cover. In this manner, recondensation of the water vapor is avoided since this hot air maintains in the vacuum chamber the temperature necessary to maintain the vapor layer.

Accordingly, it is an object of the present invention to provide a machine for drying, under vacuum, hides or skins which effectively eliminates the aforementioned disadvantages encountered with the prior art constructions.

It is another object of the present invention to provide a vacuum-drying machine for hides or skins which effectively prevents recondensation during opening of the cover, yet is simple and sturdy in construction and easy to operate.

A further object of the present invention resides in the provision of a machine for vacuum-drying tanned hides which assures more perfectly dried hides and improved appearance thereof.

These and other objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawing which shows, for purposes of ii- 3,253,351 Patented May 31, 1966 lustration only, one embodiment in accordance with the present invention, and wherein FIGURE 1 is an elevational view partly in cross-section of a machine in accordance with the present invention, and

. FIGURE 2 is a perspective view of the machine in accordance with the present invention illustrating the upper part thereof in the raised position and partially in crosssection so as to illustrate the arrangement of the various elements constituting the upper part.

Referring now to the drawing wherein like reference numerals are used throughout the two views to designate like parts, reference numeral 1 designates in FIGURES 1 and 2 the upper surface formed by the lower part of the machine in accordance with the present invention which constitutes a sturdy table or base portion generally designated by reference character B. The skins or hides to be dried are placed on the surface 1 of the base portion B which surface 1 is heated by heating means 2 (FIG- URE l) of any appropriate, known construction.

It is the part of the machine disposed above the surface 1 and generally designated by reference character A which includes the improvements to which the present invention is directed.

The upper part A functions like a sturdy cover whose peripheral tightness is assured by elastic seal means 3 and which is hingedly connected with respect to the lower base portion B by any conventional means in such a manner that it may be selectively raised and lowered, as also indicated in FIGURE 2.

The upper part A is effectively constituted by different compartments and elements which, when viewed in the direction from bottom to top, are as follows:

A layer of felt 4 which comes into contact with the skins to be dried, and superimposed thereon, a wide-mesh lattice-type element 5 against which rests a perforated plate 6.

This perforated plate 6 forms the lower wall of the vacuum decompression chamber 7.

All of the elements of the upper part A so far described, which rest on the hides or skins to be dried with a certain pressure, favor the stretching of the hides or skins thereby rendering the appearance thereof perfectly smooth and the luster of the upper part of the hides perfectly even.

The aforementioned decompression chamber 7 is in direct contact with the upper heating plate 8 of any known appropriate construction of conventional nature while the upper heating plate 3, inturn, is contiguous to the aircollecting and heating chamber 9 for the air.

The volume of the air-collecting and heating chamber 9 is substantially equal to that of the decompression chamber 7 in such a manner as to enable the necessary volumetric exchange.

A conduit or pipe 10 provided with valve means 11 of any appropriate conventional construction establishes .a selectively controllable communication between the vacuum chamber 7 and the heating chamber 9. Apertures 12 which may also be suitably opened and closed provide for the admission of fresh atmospheric air into the heating chamber 9. The control of the valve means 11 and/or of the apertures 12 may be realized in any known manner, for instance, manually or automatically from control unit C.

During the evacuation phase, the suction air is evacuated in the direction of arrows x and the conduit 10 is provided for that purpose with a check valve in the valve means 1 1, operatively arranged, for instance, in parallel with selectively actuatable valve means for the readmission of preheated equalization air.

The heated air which is preheated in chamber 9 after admission through apertures 12 passes through the chan- (3 nel or conduit 10 in the direction of arrow y into the vacuum chanrber 7 upon actuation of the valve means 11 during the phase of pressure equalization preceding the opening of the cover member A.

The machine in accordance with the present invention also includes the conventional control and regulating means, for instance, located within the control unit generally designated by reference character C, such as the means for producing the vacuum, the means for controlling the temperature, the means for stopping and opening the circulation of air through the channel or duct 10 by actuation of the valve means 1 1, and the electrical or hydraulic apparatus for the automatic opening and closing of the various parts of the machine, as well as the thermostatic temperature-regulating devices thereof.

While I have shown and described herein one embodiment in accordance with the present invention, it is understood that the same is not limited there-to, but is susceptible of many changes and modifications with-in the spirit and scope thereof as known to a person skilled in the art, for example, as regards the dimensions and the materials used to realize the present invention, which may be varied at will so as to correspond to the particular exigencies of the prevailing use thereof; accordingly, I do not wish to be limited to the details shown and described herein which are shown and described only for illustrative purposes, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. In a vacuum-drying machine for drying tanned hides and the like, and having a base structure provided with a heated surface on which are placed the hides to be dried, and a cover structure operatively associated with said base structure and effectively providing a space adapted to be carried under vacuum,

the improvement essentially consisting of vacuum chamber means in said cover structure remaining heated continuously during operation including heating means for said chamber means and means for producing a vacuum therein, and means effectively forming further chamber means in said cover structure adjoining said heating means for heating relatively colder air prior to admittance thereof into said vacuum chamber means and operable prior to opening of the cover structure to prevent recondensation within said vacuum chamber means.

2. In a vacuum-drying machine for drying tanned hides and the like, and having a base structure provided with a heated surface on which are placed the hides to be dried, and a cover structure operatively associated with said base structure and effectively providing a spac adapted to be carried under vacuum,

the improvement essentially consisting of vacuum chamber means in said cover structure remaining heated continuously during operation including heating means for said chamber means and means for producing a vacuum therein, and means effectively forming further chamber means in said cover structure adjoining said heating means for heating relatively colder air prior to admittance thereof into said vacuum chamber means and operable prior to opening of the cover structure to prevent recondensation within said vacuum chamber means,

said two chamber means having about the same volume.

3. In a vacuum-drying machine for drying tanned hides and the like, and having a base structure provided with a heated surface on which are placed the hides to be dried, and a cover structure operatively associated with said base structure and effectively providing a space adapted to be carried under vacuum,

the improvement essentially consisting of vacuum chamber means in said cover structure remaining heated continuously during operation including heating means for said chamber means and means for producing a vacuum therein, and means effectively forming further chamber means in said cover structure adjoining said heating means for heating relatively colder air prior to admittance thereof into said vacuum chamber means and operable prior to opening of the cover structure to prevent recondensation within said vacuum chamber means,

said two chamber means having about the same volume and control means including first means for initially admitting outside air into said further chamber means to pre-heat therein the outside air, second means for selectively enabling the flow of pre-heated air into said vacuum chamber means, and third means for thereafter opening said cover structure.

4. In a vacuum-drying machine for drying tanned hides and the like, and having a base structure provided with a heated surface onwhich are placed the hides to be dried, and a cover structure operatively associated with said base structure and effectively providing a space adapted to be carried under vacuum,

the improvement essentially consisting of first means in said cover structure forming a vacuum chamber remaining heated continuously during operation of the machine, heating means for said vacuum chamher, and pressure equalization means and means for producing a vacuum therein operable prior to opening of the cover structure including means effectively pro-heating relatively colder atmospheric air prior to admittance into said vacuum chamber to thereby prevent recondensation.

5. In a vacuum-drying machine for drying tanned hides and the like, and having a base structure provided with a heated surface on which are placed the hides to be dried, a .cover structure operatively associated with said base structure and effectively providing a space adapted to be carried under vacuum, and means for producing a vacuum in said space,

the improvement essentially consisting of first means in said cover structure operatively associated with said base portion to provide an evacuated drying space and including a first layer operable to adhere to the hides during the drying operation, a widemesh member on said first layer, and a perforated plate on the side of said wide-mesh member opposite said first layer and constituting the lower wall of a vacuum chamber, upper heating means above said perforated plate,

and second means in said cover structure forming a preheating space adjoining said upper heating means for heating relatively colder air prior to admittance into said evacuated space.

6. In a vacuum-drying machine for drying tanned hides and the like, and having a base structure provided with a heated surface on which are placed the hides to be dried, and a cover structure operatively associated with said base structure and effectively providing a space adapted to be carried under vacuum,

the improvement essentially consisting of vacuum chamber means in said cover structure remaining heated continuously during operation including heating means for said chamber means and means for producing a vacuum therein, and means effectively forming further chamber means in said cover structure adjoining said heating means for heating relatively colder air prior to admittance thereof into said vacuum chamber means and operable prior to opening of the cover structure to prevent recondensation within said vacuum'chamber means,

and control means including first means initially admitting outside air into said further chamber means to pre-heat therein the outside air, second means for selectively enabling the flow of preheated air into said vacuum chamber means, and third means for thereafter opening said cover structure.

5 6 7. In a vacuum-drying machine for drying tanned and control means for controlling the evacuation of hides and the like, and having a base structure provided air from said drying space and for controlling the with a heated surface on Which are placed the hides to admission of pre-heated air from said preheating be dried, a cover structure operatively associated with space to said drying space. said base structure and effectively providing a space 5 adapted to be carried under vacuum, and means for pro- References cued by the Exammer ducing a vacuum in said space, v UNITED STATES PATENTS the improvement essentially consisting of first means 1 4 5 1 19 Dow 4 9 in said cover structure operatively associated with 1 9 0 697 5/1934 Cochran et 1 34 145 said base portion to provide an evacuated drying 10 1,965,958 7/1934 Jonsson 34-92 space and including a first layer operable to adhere 2,321,756 6/1943 Kyle 34-145 to the hides during the drying operation, a wide- 2,618,073 11/1952 Finzer 34-146 mesh member on said first layer, and a erforated 2,686,976 8/1954 Houghton 34-143 plate on the side of said wide-mesh member opposite 15 3,088,219 5/ 1963 Kraus 349 said first layer and constituting the lower wall of a 1 9 10/1964 Turato X vacuum chamber, upper heating means above said perforated plate, WILLIAM F. ODEA, Przmary Examzner.

and second means in said cover structure forming a NORMAN YUDKOFF, ROBERT preheating space adjoining said upper heating means min for heating relatively colder air prior to admittance F E DRUMMQND, W, E, WAYNER, into said evacuated space, Assistant Examiners. 

1. IN A VACUUM-DRYING MACHINE FOR DRYING TANNED HIDES AND THE LIKE, AND HAVING A BASE STRUCTURE PROVIDED WITH A HEATED SURFACE ON WHICH ARE PLACED THE HIDES TO BE DRIED, AND A COVER STRUCTURE OPERATIVELY ASSOCIATED WITH SAID BASE STRUCTURE AND EFFECTIVELY PROVIDING A SPACE ADAPTED TO BE CARRIED UNDER VACUUM, THE IMPROVEMENT ESSENTIALLY CONSISTING OF VACUUM CHAMBER MEANS IN SAID COVER STRUCTURE REMAINING HEATED CONTINUOUSLY DURING OPERATION INCLUING HEATING MEANS FOR SAID CHAMBER MEANS AND MEANS FOR PRODUCING A VACUUM THEREIN, AND MEANS EFFECTIVELY FORMING FURTHER CHAMBER MEANS IN SAID COVER STRUCTURE ADJOINING SAID HEATING MEANS FOR HEATING RELATIVELY COLDER AIR PRIOR TO ADMITTANCE THEREOF INTO SAID VACUUM CHAMBER MEANS AND OPERABLE PRIOR TO OPENING OF THE COVER STRUCTURE TO PREVENT RECONDENSATION WITHIN SAID VACUUM CHAMBER MEANS. 